1. Field of the Invention
The present invention relates to devices for manufacturing printed circuit boards and, particularly, to a coverlay processing system for a printed circuit board.
2. Description of Related Art
With the development of science and technology, integrated circuits, such as portable devices and the like, require ever greater degrees of miniaturization and weight reduction. To meet these requirements, the degree of circuit integration is increasing. As part of the increase in circuit density, the width of traces, gaps between traces, and the diameter of via are becoming smaller. To accommodate these developments, flexible printed circuit boards have been developed.
A typical flexible printed circuit board includes a base film and a copper film disposed on a surface of the base film. Conductive traces are disposed on the copper film. A coverlay is arranged on the conductive traces for protecting the conductive traces against damages. In order to accommodate structures and sizes of the flexible printed circuit board, the coverlay is cut/sheared by a cutting machine using a roll-to-roll process. Referring to FIG. 4, a coverlay is moved by a conveyance device 30 to a cutting machine 20. The coverlay includes a first segment 11 adjacent to the cutting machine 20, a second segment 12 adjacent to the conveyance device 30. In the process of transmitting the coverlay, once the first segment 11 reaches a location adjacent to the cutting machine 20, the first segment 11 will freewheel to the cutting machine 20. The second segment 12 is driven by the conveyance device 30 to move towards the cutting machine 20. A moving speed of the first segment 11 is less than that of the second segment 12. As a result, an arched segment 13 may be formed between the first segment 11 and the second segment 12. At the moment, the cutting machine 20 continues to cut the coverlay according to the original speed, thus the arched segment 13 of the coverlay may be cut improperly.
Therefore, a coverlay process system, which can avoid the improper cutting, is desired.